This invention relates to free electron lasers and other spontaneous radiation generating systems and in particular to a new and improved high gain helical magnet and its application to such devices and systems.
Conventional lasers are based on the radiation emitted by an electron bound to an atom or molecule. In the free electron laser the initial and final states of the electron correspond to specific states of motion of an electron in a spatially periodic magnetic field. Both the initial and final states are free. The free electron laser is described in detail in U.S. Pat. No. 3,822,410 of John M. Madey entitled STIMULATED EMISSION OF RADIATION IN PERIODICALLY DEFLECTED ELECTRON BEAM, issued July 2, 1974.
State of the art devices of this type have utilized magnets that permit only limited gain and require position and angular correction of the inserted and extracted beam. The same deficiencies limit the effectiveness of the simple transverse magnets commonly used in the generation of spontaneous radiation.
There currently exists, therefore, the need for magnet means for use in such devices and systems that provides improved system gain and eliminates complex and costly beam insertion and extraction compensation. The present invention comprehends a double helix periodic magnet that satisfies this need.